First and foremost, the floor is in! I didn’t glue the front floor in just yet but the main floor is epoxied down. I removed those cheap fuel tank straps and installed 4 really nice heavy duty aluminum angle. The hat he gutters are glued and glassed down as well. It took 5 quarts of epoxy mixed with fumed silica to cover both stringers and about 2 quarts to fill the edges and seams.

I got pretty good at matching gelcoat on older boats. White gelcoat with a drop or 2 of brown pigment usually gets you real close to that stained gelcoat color. Shoot it with a PreVail sprayer and you can easily tint as needed.

I'm not sure plywood is a good choice for exposed marine environment. I used Brazilian Mahogany and it has held up for about 15  years. If it gets funky, a quick scruff with 120 grit and re-oil with tong oil.

Thanks, guys.  The wall of the deck liner underneath the gunnel is directly behind it.  This has a good 4-5 inch crack in it, as well, right at where the wall and deck meet.  The interior crack didn't appear until I walked near it a bit (or I didn't notice it for a while--my heart rate was up pretty good because the impact felt very hard and I was about 30 miles offshore). 

I can contort my arm around and just barely reach it from the back, so if I need to do anything on the back except place a backer, I'll have to cut an access hole, but I've already got to do repairs on the interior crack, so I guess it's not the end of the world.

I'm most worried about matching the gelcoat.  I kind of think there is not a chance.  The boat is 20 years old and different parts of the hull are different colors due to variable fading.  I think I'm just going to try white gelcoat and add pigment it to match as close as possible.

Hey Rickk
Want to redo another 170 this winter !!??
I need to replace the whole floor and get some weight out of her!